Pressing, imperative (6)
I believe the answer is:
urgent
This clue is a double definition.
'pressing' is the first definition.
(I know that pressing can be written as urgent)
'imperative' is the second definition.
(similar in meaning)
(Other definitions for urgent that I've seen before include "Critical" , "In need of immediate action" , "Pressing, burning" , "To be done asap" , "demanding speedy action" .)